README

The JsonSerializer that comes with this library is a very simple serializer/deserializer which recursively converts an object graph to and from JSON, without any configuration or custom code. Its design goals are:

• Users shouldn't be forced to add custom configuration to their existing classes.
• Users shouldn't need to write any supporting code.
• The solution should take care of as few edge cases as possible.
• The solution should be as small as possible, without becoming useless (<=100 LOC).
• The solution should warn the user about its limitations using descriptive exceptions.

In order to make this work, this library restricts you to using only values of type:

• null
• scalar (int, float, bool)
• user-defined objects (so no built-in PHP classes like \DateTimeImmutable)
• arrays where every value is of the same type (maps or lists)
• and any combination of the above

Furthermore, you need to define the types you used in standard @var docblock annotations (as you probably already do), e.g.

/**
 * @var string
 *
 * @var int
 *
 * @var bool
 *
 * You can use a relative class name:
 *
 * @var ClassName
 *
 * Or a full class name:
 *
 * @var Fully\Qualified\Class\Name
 */

Of course, every property should have just one @var annotation.

For simple types, you can use PHP native property types as well:

private string $string;
private int $int;
private bool $bool;
private ClassName $object;

array-typed properties still require an additional @var annotation. You can define lists of the above types by simply adding [] to the @var annotation, e.g.

/**
 * @var Fully\Qualified\Class\Name[]
 */
private array $array;

To work around the limitation that you can't use PHP's built-in classes, simply convert the data internally to something else. For example, to use a \DateTimeImmutable timestamp:

/**
 * @var string
 */
private $timestamp;

public function __construct(\DateTimeImmutable $timestamp)
{
    $this->timestamp = $timestamp->format(\DateTime::ISO8601);
}

public function getTimestamp() : \DateTimeImmutable
{
    return \DateTimeImmutable::createFromFormat(\DateTime::ISO8601, $this->timestamp);
}

To use the serializer:

// create an object
$object  = ...;

$serializedData = Serializer::serialize($object);

// $serializedData will be a pretty-printed JSON string

To deserialize the data:

$restoredObject = Serializer::deserialize(
    Fully\Qualified\Class\Name::class,
    $serializedData
);

// $restoredObject will be of type Fully\Qualified\Class\Name

You can force the (de)serializer to ignore certain properties by adding @ignore somewhere in its doc block:

final class IgnoredProperty
{
    /**
     * @var array<object>
     * @ignore
     */
    public $events = [];

    /**
     * @var string
     */
    public $foo;
}

If you like, you can create an instance of JsonSerializer and call its object methods instead of Serializer's static methods.

Thanks

This library stands on the shoulders of the phpdocumentor/reflection-docblock library, which does all the work related to property type resolving.